Delimiter characters are not included in the elements of the returned array.

If this instance does not contain any of the characters in separator, the returned array consists of a single element that contains this instance. If the separator parameter is null or contains no characters, white-space characters are assumed to be the delimiters. White-space characters are defined by the Unicode standard and return true if they are passed to the Char.IsWhiteSpace method. However, if the separator parameter in the call to this method overload is null, compiler overload resolution fails. To unambiguously identify the called method, your code must indicate the type of the null. The following example shows several ways to unambiguously identify this overload.

Each element of separator defines a separate delimiter character. If the options parameter is RemoveEmptyEntries and the length of this instance is zero, an empty array is returned.

If the options parameter is None, and two delimiters are adjacent or a delimiter is found at the beginning or end of this instance, the corresponding array element contains Empty.

Performance Considerations

The Split methods allocate memory for the returned array object and a String object for each array element. If your application requires optimal performance or if managing memory allocation is critical in your application, consider using the IndexOf or IndexOfAny method, and optionally the Compare method, to locate a substring within a string.

If you are splitting a string at a separator character, use the IndexOf or IndexOfAny method to locate a separator character in the string. If you are splitting a string at a separator string, use the IndexOf or IndexOfAny method to locate the first character of the separator string. Then use the Compare method to determine whether the characters after that first character are equal to the remaining characters of the separator string.

In addition, if the same set of characters is used to split strings in multiple Split method calls, consider creating a single array and referencing it in each method call. This significantly reduces the additional overhead of each method call.

Notes to Callers

In the .NET Framework 3.5 and earlier versions, if the Split method is passed a separator that is null or contains no characters, the method uses a slightly different set of characters to split the string than the Trim method does to trim the string. In the .NET Framework 4, both methods use an identical set of Unicode white-space characters.

// This example demonstrates the String() methods that use// the StringSplitOptions enumeration.using System;
class Sample
{
publicstaticvoid Main()
{
string s1 = ",ONE,,TWO,,,THREE,,";
string s2 = "[stop]" +
"ONE[stop][stop]" +
"TWO[stop][stop][stop]" +
"THREE[stop][stop]";
char[] charSeparators = newchar[] {','};
string[] stringSeparators = newstring[] {"[stop]"};
string[] result;
// ------------------------------------------------------------------------------// Split a string delimited by characters.// ------------------------------------------------------------------------------
Console.WriteLine("1) Split a string delimited by characters:\n");
// Display the original string and delimiter characters.
Console.WriteLine("1a )The original string is \"{0}\".", s1);
Console.WriteLine("The delimiter character is '{0}'.\n",
charSeparators[0]);
// Split a string delimited by characters and return all elements.
Console.WriteLine("1b) Split a string delimited by characters and " +
"return all elements:");
result = s1.Split(charSeparators, StringSplitOptions.None);
Show(result);
// Split a string delimited by characters and return all non-empty elements.
Console.WriteLine("1c) Split a string delimited by characters and " +
"return all non-empty elements:");
result = s1.Split(charSeparators, StringSplitOptions.RemoveEmptyEntries);
Show(result);
// Split the original string into the string and empty string before the // delimiter and the remainder of the original string after the delimiter.
Console.WriteLine("1d) Split a string delimited by characters and " +
"return 2 elements:");
result = s1.Split(charSeparators, 2, StringSplitOptions.None);
Show(result);
// Split the original string into the string after the delimiter and the // remainder of the original string after the delimiter.
Console.WriteLine("1e) Split a string delimited by characters and " +
"return 2 non-empty elements:");
result = s1.Split(charSeparators, 2, StringSplitOptions.RemoveEmptyEntries);
Show(result);
// ------------------------------------------------------------------------------// Split a string delimited by another string.// ------------------------------------------------------------------------------
Console.WriteLine("2) Split a string delimited by another string:\n");
// Display the original string and delimiter string.
Console.WriteLine("2a) The original string is \"{0}\".", s2);
Console.WriteLine("The delimiter string is \"{0}\".\n", stringSeparators[0]);
// Split a string delimited by another string and return all elements.
Console.WriteLine("2b) Split a string delimited by another string and " +
"return all elements:");
result = s2.Split(stringSeparators, StringSplitOptions.None);
Show(result);
// Split the original string at the delimiter and return all non-empty elements.
Console.WriteLine("2c) Split a string delimited by another string and " +
"return all non-empty elements:");
result = s2.Split(stringSeparators, StringSplitOptions.RemoveEmptyEntries);
Show(result);
// Split the original string into the empty string before the // delimiter and the remainder of the original string after the delimiter.
Console.WriteLine("2d) Split a string delimited by another string and " +
"return 2 elements:");
result = s2.Split(stringSeparators, 2, StringSplitOptions.None);
Show(result);
// Split the original string into the string after the delimiter and the // remainder of the original string after the delimiter.
Console.WriteLine("2e) Split a string delimited by another string and " +
"return 2 non-empty elements:");
result = s2.Split(stringSeparators, 2, StringSplitOptions.RemoveEmptyEntries);
Show(result);
}
// Display the array of separated strings.publicstaticvoid Show(string[] entries)
{
Console.WriteLine("The return value contains these {0} elements:", entries.Length);
foreach (string entry in entries)
{
Console.Write("<{0}>", entry);
}
Console.Write("\n\n");
}
}
/*
This example produces the following results:
1) Split a string delimited by characters:
1a )The original string is ",ONE,,TWO,,,THREE,,".
The delimiter character is ','.
1b) Split a string delimited by characters and return all elements:
The return value contains these 9 elements:
<><ONE><><TWO><><><THREE><><>
1c) Split a string delimited by characters and return all non-empty elements:
The return value contains these 3 elements:
<ONE><TWO><THREE>
1d) Split a string delimited by characters and return 2 elements:
The return value contains these 2 elements:
<><ONE,,TWO,,,THREE,,>
1e) Split a string delimited by characters and return 2 non-empty elements:
The return value contains these 2 elements:
<ONE><TWO,,,THREE,,>
2) Split a string delimited by another string:
2a) The original string is "[stop]ONE[stop][stop]TWO[stop][stop][stop]THREE[stop][stop]".
The delimiter string is "[stop]".
2b) Split a string delimited by another string and return all elements:
The return value contains these 9 elements:
<><ONE><><TWO><><><THREE><><>
2c) Split a string delimited by another string and return all non-empty elements:
The return value contains these 3 elements:
<ONE><TWO><THREE>
2d) Split a string delimited by another string and return 2 elements:
The return value contains these 2 elements:
<><ONE[stop][stop]TWO[stop][stop][stop]THREE[stop][stop]>
2e) Split a string delimited by another string and return 2 non-empty elements:
The return value contains these 2 elements:
<ONE><TWO[stop][stop][stop]THREE[stop][stop]>
*/